Improvement in turning-lathes



PATENT OFFICE.

FOLBERT KIRST, OF WESTFIELD, MASSACHUSETTS.

IMPROVEMENT IN TU RNING-LATHES.

Specification forming part of Letters To all whom 'it may concern l Beit known that I, FoLnnnT KIRsr, of Vestiield, in the county of Hampdenand Oommonwealth of Massachusetts, have invented a new and ImprovedChuck for Turning-Lathes 5 and I do hereby declare that the following isa full, clear, and exact description of the same, referencebeinghad tothe accompanying drawings, making a part of this specification- Theobject of my invention is to produce a chuck for a lathe which shall becapable of holding a variety of work, and at the same time hold eachpiece perfectly central. Some parts are more especially designed forwatchA work, and generally the whole construction is more adapted forsmall work than for large, yet a large chuck constructed on the sameprinciple would be very useful for many kinds of work.

In the drawings, Figure 1 is a side view of a lathe with my inventionattached. Fig. 2 is an end view of the same. Fig. 3 is a side view ofthe chuck, drawn to a larger scale; Fig. 4, an end view, and Fig. 5 alongitudinal section, of the same.

Like letters of reference indicate corresponding parts in each of theseveral figures.

A is the frame or support.

B is the support for rest C.

D D are bearings Vfor the spindle E.

F is the driving-pulley on E.

a a a are three jaws pivotcd to the head I) ofthe chuck.

b is made fast to the end of spindle E.

c is a conical collar ttingperfectly to E and turned exactly concentricwith the same.

d is a rod running through the spindle E and attached to the collar c ate.

f is a screw on cl, fitting in a corresponding nut on the inside ofspindle E.

g g g are screws in the back ends of a a a. These screws are adjusted sothat when the heads are screwed down onto the jaws a a a, and the pointsresting on the collar c the points of the jaws ,at l 2 3 will holdapiece exactly concentric with the spindle. Now, the circumference ofeach of thc large screwheads is divided into four equal parts, and acorresponding mark made on the top of etch jaw where it comes in contactwith the circumference of the head. Thus, if these screws are turned outit allows the back ends of the Patent No. 43,5 l 2,dated July l2, 1864antedatcd July 6, 1864.

jaws a a a to come nearer to the conical collar c, and consequentlyallows the points of the jaws at 1 2 3 to open farther, and thereforereceive a larger piece of work 5 but if one screw should be turned outmore than another the jaws would not hold the work central. Thereforethe heads are provided with the marks or points before mentioned, sothat it can be seen when each screw has been turned just one, two, orthree quarte-rs. Of course, finer divisions could be made, if desirable5 but the sliding collar vfurnishes the means for all nicer variations.

h is a head on the end of the rod d, by which it may be turned.

t' is a small pin or center fitting into a hole drilled exactly in thecenter of the spindle E.

K is a spiral spring behind the center t'. The front end of t' iscountersunk, so as to form a center to receive the point or center ofany small arbor or similar article to be turned.

mis a screw to hold the centert' in any given place.

H is a catch or stop, which hooks into the pulley F to confine thespindle while turning the rod d, in order to enable the operator to haveone hand free to hold the work while turning up on the screw d with theother.

Now, having described thev arrangement of the several parts, I willproceed to describe the operation, which is as follows: Suppose it isrequired to turn off an arbor or pivot belonging to a watch, first turnback the screw d, thereby drawing back the conical collar c and allowingthe front points, l 2 3, of the jaws to open. Now, loosen the screw m,thus allowing the center t' to yield to any pressure on its end, and tobe thrown out again bythe spiral spring K when said pressure is removed.To insert the piece of work above mentioned,- place the Apoint of onearbor in the countersink in the center i and press in said center untilthe points l 2 3 of the jaws a a a will take hold of the work at somesuitable point without injury to it, then tighten the screw m to confinethe center i. Next turn up on the screw-rod d, which presses the conicalcollar c against the points of the screws g g g, and consequently closesthe points l 2 3 on to the work.

N ow, I claim the advantages'of my invencollar c renders it possible tomake it very nearly perfect, as it can be turned on an arbor, andconsequently the conical surface made exactly concentric withl the holethrough its center, which can, of course, be made to tit the spindle E.Therefore, so far, all can be made practically perfect. Now, the screwsg g g can be fitted by hand so as to give perfect results when screwedentirely down, and then the index-marks can be made on the heads so thatthey will be perfect. Now, in holding lany large disk in a clutch'orchuck'it is impossible to hold it exactly square by the circumferencealone, and if it has a projecting arbor it can not readily be brought upto a face-plate. Now, in such a case, the arbor is pressed against thecenter e', which yields to the pressure until the work is in a suitableposition to be held by thejaws a a a also, lin ease of a piece ofwork-such as apinionhaving two arbors and an intermediate portion largerthan the arbors, but which is not suitable to be clutched by the jaws ofa chuck, as in case of the teeth ot' the pinion, then the peculiar formof thejaws a a a" allows them to reach over such portion and clutch thearbor beyond. Thus I claim two advantages in my invention-rst, themanner of construetion, whereby it is rendered possibleto attain greataccuracy in manufacturing; and, secondly, its convenience forgeneral'use when completed. Y

Now, having fully described the construction and operation of myinvention, I do not claim the jaws a a a independently or in combinationwith the conical collar c when used independently ofthe other parts ofmy invention or for other purposes than that` specified iu mydescription g but What I do claim as new, and desire to secure byLetters Patent, is-

The adjustable center fi, in combination with the jaws a a a" and lset-screw m, when used for the purpose and in the manner hereindescribed, and forming a part of a chuck for a turning-lathe. r

l FOLBERT KIRST. Witnesses:

MILTON BRADLEY, J. B. GARDINER.

